Association of preoperative total lymphocyte count with prognosis in resected left-sided pancreatic cancer

Background: Immunologic factors such as neutrophil-lymphocyte ratio and platelet-lymphocyte ratio play an important role in predicting the oncologic outcome of patients in pancreatic ductal adenocarcinoma (PDAC). It is hypothesized that host immunity represented by total lymphocyte count at diagnostic stage would influence oncologic outcome in left-sided PDAC. Methods: Between January 1992 and August 2017, total of 112 patients who underwent distal pancreatectomy for left-sided PDAC were included and analysed. Results: At the time of the diagnosis, total lymphocyte count at diagnosis of left-sided PDAC was 1.8 ± 0.7 10 ³ /μL (mean value ± standard deviation). Among different cut-off values, 1.7 showed most powerful significant differences in long-term oncologic outcomes. The patients with preoperative lymphocyte count (≤1.7) was associated with early recurrence (median 8.4 months versus 18.1 months, P = 0.011) and shorter survival (median 18.6 months versus 35.9 months, P = 0.028). Patients with preoperative total lymphocyte count over 1.7 showed higher white blood cell count (P < 0.001), platelet count (P = 0.039), neutrophil count (P = 0.004) and monocyte count (P = 0.001). However, more interestingly, neutrophil-lymphocyte ratio (P < 0.001) and platelet-lymphocyte ratio (P < 0.001) were found to be significantly higher in those with total lymphocyte count less than 1.7. Lymphocyte to monocyte ratio was inversely related to preoperative total lymphocyte count (P < 0.001). Only age was identified to be significantly different (P = 0.007). However, other clinicopathological parameters generally known to be related to tumour aggressiveness, were not different between two groups. Conclusion: In conclusion, preoperative total lymphocyte at diagnostic stage is simple, and good prognostic factor in left-sided pancreatic cancer.